Different types of laboratory mixers for the preparation of samples are known. Certain mixers are designed for the preparation of a sample before its microbiological analysis.
Typically, preparation of a sample to be analyzed begins with inserting the sample into a flexible sterile bag, usually made of a transparent plastic material. A diluent solution, usually physiological serum, is added to the bag. A supporting device, such as a blade mixer, can then be situated on a static surface and operated horizontally against the bag containing the sample to be analyzed.
The mechanism of a typical mixer consists of two blades. The blades grind the sample, if it is a solid, to homogenize the sample prior to microbiological investigation. However, the samples to be analyzed are often of various dimensions with varying external surfaces that may be sharp and jagged. As a result, the sterile bag may be pierced or a leak may be caused. In this regard, it will be noted that any contact between the sample and the inner parts of the mixer causes cross contamination. As a consequence, the entire preparation process must be restarted from the beginning, and the interior of the mixer must be completely cleaned.
A number of inventors have sought to provide improved mixers. Often, such inventors seek as a fundamental goal to preserve the integrity of the sample.
For example, French Patent No. 2795658 B1 describes a mixer that allows the mechanical action of the blades to adjust to the dimensions of the sample. With that, deterioration of the sterile bag is sought to be prevented. However, any adjustments are made at the discretion of the operator and are not guaranteed to be accurate or beneficial. Consequently, despite the adjustments, the mechanical action may still lead to leaks and accidental perforation.
In view of the foregoing, it will be appreciated that there is a continued need for a laboratory mixer for samples that enables an effective mixing of samples while avoiding piercing and other damage to the sample container and while preventing sample and apparatus contamination.